Twin-plug ignition

[andyjboy]

I currently have a 2.5 litre short-stroke twin-plug engine that I'm putting in my 911R-inspired car.

The engine is currently equipped with an Electromotive crank-fire ignition system but I want to switch to a Marelli-style distributor for the 'old school' look.

What are my options in terms of distributor - I'm talking about the modern 'converted' distributors which use readily-available Jaguar Marelli caps (like Aaron's) rather than original Marelli twin-plug distributors ?

Can I simply remove the crankfire system (including crank pulley/trigger) & fit a twin-plug distributor/CDI boxes or is it more complicated than this ?

Does anyone offer a 'mini' wiring harness already made up ?

[Henry Schmidt]

We can make a distributor that will drop straight into your engine.
Our distributor is built with an advance curve specifically designed for the engine it is intended for.
We can even build a distributor that employs points to trigger the CD boxes as is required by some FIA vintage regulations.
Although Aaron is closer to offering an absolutely stellar Marelli replica, at this time the Supertec conversion is the best option available today.

[Henry Schmidt]

If your 2.5 short stroke is built using the early case design we also make a custom pointless twin plug distributor that fits the 27 mm hole and clamp style hold down.
This distributor come with the same attention to detail as the 30 mm version and can also be built with or without points.
They are being used in engine across the globe for both street and track applications. Because the internal electronics are stock Bosch components you can have complete confidence in the reliability of these products.

[andyjboy]

Sent you an email Henry.

[andyjboy]

I've tried emailing you directly (twice) but the emails bounced back so I've sent another via this board.

[andyjboy]

Email sent via Pelican has been bounced back

- sent you a pm

[MBruns]

Andy, take a look at the unit we build, and do a search on Pelican for Minkoff he has a 2.0 and a 2.5 that both have our distributors in with some pics posted here, our web site is JBRacing.com We have them in street cars as well as Race cars with great results.
Let me know if I can be of help, Mike Bruns

[Henry Schmidt]

Originally Posted by andyjboy

Email sent via Pelican has been bounced back

- sent you a pm

Email issue has been resolved.
Cheers

[Tom C.]

Andy,

Give Steve Wiener a call (503) 244-0990 http://www.rennsportsystems.com/. He offers a nice unit and is a wealth of knowledge.

Tom

[Turbo_pro]

Originally Posted by MBruns

Andy, take a look at the unit we build, and do a search on Pelican for Minkoff he has a 2.0 and a 2.5 that both have our distributors in with some pics posted here, our web site is JBRacing.com We have them in street cars as well as Race cars with great results.
Let me know if I can be of help, Mike Bruns

Mike
I wonder if you could post some pictures of your distributor. I am especially interested in a close up of your rotor. I heard it was a little funky.
I have also heard that some of your distributors have no advance. How does that work? Do you build distributors with a custom advance curve?

Tom
I went to Steve Wiener's web site and didn't see a twin plug distributor.

Why doesn't everyone post pictures of all the options so we can compare the various products?

Isn't there another distributor made by Jarvis Tech? Has anyone seen that one?

[efhughes3]

Originally Posted by Henry Schmidt

Email issue has been resolved.
Cheers

I sent you a couple of e-mails Henry a week or two ago, they didn't come back, but I didn't get a reply.

[Plavan]

Andy- here is a link to another twin plug example that a couple people use in VARA with good results.
http://www.jbracing.com/enginecomp.php

[Henry Schmidt]

Originally Posted by efhughes3

I sent you a couple of e-mails Henry a week or two ago, they didn't come back, but I didn't get a reply.

Hi Ed
The email is functioning again so try me if you want. It would be my pleasure to assist you in any way I can.

BTW: for those of you who send email and don't get a response, I'm sorry. I get nearly 200 email a day so sometimes your emails fall through the cracks. I try to answer every email personally but it is a monumental task.
Cheers

As for Chad Plavan's assertion that some drivers in VARA run JB Racing distributors, my only comment is there are all kinds of products for all kinds of requirements. Not everyone has the same criteria for the items they purchase. For street cars an advance curve custom to a specific engine is paramount. In a race engine advance curves are somewhat less critical. This can be illustrated by the fact that many factory Porsche racing distributors (935, 917 just to mention two) had no advance. Would these work well in a street application? Not Hardly.

[Plavan]

The jbracing dist. is user adjustable in 5 degree increments. Personally, i think versatility is key if you want to ever change motors or setup. Or if you ever want to resale the dist. for that matter.

[MBruns]

I will post some pics on Monday when I get to work that will show how the rotor and platform works as well as the adjustability of the advance mech. or the ability to lock it out and set the timing to what you want to run total (like most all the factory race cars did) It is made from billet alum. and has seals ball bearings and a bushing at the bottom, custom gears for all engines incl. CCW for the SC

Thanks, Mike Bruns JBRacing.com

[MBruns]

JB Racing Distributor Technical Information

First, I would like to thank everyone for expressing an interest in JB Racing’s distributor. I have posted some additional pictures of the distributor, magnetic sensors, rotor assembled on the rotor platform, rotor platform and rotor assembly.

The design criteria for our distributors was focused upon building a complete billet assembly out of modern, currently available components.

JB Racing distributors are available as complete units with cap and rotor, hold down clamp, o-ring seal, all necessary hardware and instructions.

JB Racing’s 12-pin, twin-plug distributors for Porsche 911 air-cooled engines feature internal ignition triggering with an adjustable advance curve. All distributor housings are one piece, CNC machined from billet aluminum, and incorporate ball bearings, bronze bushings and internal shaft seals.

There are several configurations of this distributor, depending on the engine and application you may have. Our distributors will cover engine displacements from 2.0 liter through 3.8, including the SC engines which the distributor turns counter-clockwise.

We use factory equivalent heat treated distributor drive gears. These drive gears have a tooth profile that is an exact replica of the OEM gear.

The internal ignition triggering system is made up of two magnetic pick-ups and a six pole reluctor. This enables you to have two completely separate ignition systems. One for the top plugs and one for the bottom plugs. The only common denominator in the system is the rotor itself. Some customers choose to use one magnetic pick-up to trigger both ignitions systems, thus leaving one magnetic pick-up as a backup.

These magnetic pick-ups will trigger OEM, MSD, and Mallory CD boxes. They may also be used with other CD box manufacturers that are compatible with magnetic triggering.

All of JB Racing’s internally triggered distributors have advance curve capabilities. Typically, if a distributor is going into a street application, we set up the advance curve when we build the distributor. If the distributor is going into a track car or racing application, we have determined that these engines perform better with no curve in the distributor. All you need to do is time the engine at whatever total advance you want to run. The advance curve mechanism is still in the distributor and is available to be used at a later date if the distributor finds its way into a different application. The advance curve is field adjustable and is covered in detail in the instructions.

In designing the rotor components, we focused on making the rotor simple and inexpensive. Thus the development of what we call the rotor platform. This is the black piece that you see in the pictures. The rotor platform is secured to the top of the distributor shaft and the rotor is bolted to the rotor platform. When it comes time to replace the rotor, you simply unbolt it from the rotor platform. The new replacement rotor you receive from JB Racing includes the new rotor button and lower plug brass contact piece. The rotor platform also serves as a shield for the electrical components underneath.

All of our distributor caps, including replacement caps, come with a wiring placard (see pictures). This makes installing the sparkplug wires very simple. It has been our experience that most rotor and distributor cap damage is caused by miswiring. I have posted two pictures of distributor caps with placards, one being for clockwise rotating distributors, the other for counter-clockwise rotating distributors.

I have also posted a few additional pictures that show distributors installed in engines and other accessories that are available to complete your twin plug ignition package.

I hope this additional information answers some of the questions you had about the distributor. I would be happy to answer any additional questions you may have concerning the distributor, how it functions and/or applications.

[michel richard]

Mike, Henry,

I'm trying to buy a rotor like the one on the right in the picture above. I phoned JB Racing this morning (may have been speaking to you, Mike, not sure) and ordered a part called "Twin-Plug Distributor Rotor Assembly - replacement" but something later tweaked my attention. It appears that this assembly consits only of the brass contacts on the black portion of the rotor. I thought this fact could have been better explained - in my mind a "distributor rotor" includes everything between the distributor shaft and the cap contacts. In any event, I was able to cancel my order no problem, no harm done.

In any event, I would like to buy the part that is shown on the right above. It appears to be a single part. Where can I get it ?

TIA

Michel Richard

[michel richard]

BTW, I did check on our host's site, without success

[MBruns]

Here are a few close up photos

[Henry Schmidt]

Originally Posted by michel richard

Mike, Henry,

I'm trying to buy a rotor like the one on the right in the picture above. I phoned JB Racing this morning (may have been speaking to you, Mike, not sure) and ordered a part called "Twin-Plug Distributor Rotor Assembly - replacement" but something later tweaked my attention. It appears that this assembly consits only of the brass contacts on the black portion of the rotor. I thought this fact could have been better explained - in my mind a "distributor rotor" includes everything between the distributor shaft and the cap contacts. In any event, I was able to cancel my order no problem, no harm done.

In any event, I would like to buy the part that is shown on the right above. It appears to be a single part. Where can I get it ?

TIA

Michel Richard

The rotor in the picture is the art, heart and soul of the Supertec distributor.
Is was designed by Aaron Burnham (BurnBros) and is only manufactured by BurnBros. The rotor and cap are a direct replacement for the Marelli factory distributor as used on RSR, 911R 910 906. The genuine Marelli cap and BB rotor combination can be ordered through Supertec exclusively. We sell the cap and rotor as a set to prevent the owner from inadvertently using the horrible, plastic, aluminum post replica cap that is so tempting by it's price yet totally inferior in materials and tolerances.
The Supertec distributor uses many parts that are direct replacement parts for the Marelli racing distributor. The upper housing piece and the bearing retainer were copied from the original factory piece.
Aaron is in production of an exact Marelli distributor and when it is completed and tested it will be for sale directly through a BurnBros website (not yet up and running) as well as Supertec Performance..



2.8 RSR Marelli

Supertec with BurnBros